A high molecular weight mucoprotein from normal human colon and adenocarcinomas of colonic origin will be extracted, purified and subjected to chemical and immunologic analysis. The ability of antisera to distinguish between colonic mucoprotein of normal and neoplastic origin will be investigated with an aim to determining if this material has potential as a tissue specific or tumor specific antigen. The previously described (Gold and Miller, Immunochem. 11:369, 1974) ability of this glycoprotein to bind certain cations selectively will be further explored. The ability of homologous immunization with this material to cause colonic disease will be examined in rats. In the same specie we will investigate possible alterations in this material coincident with chemically induced colonic carcinoma. Finally, we will undertake a detailed analysis of the structure of the carbohydrate prosthetic groups of this mucoprotein.